<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <style>
        
    </style>
</head>
<body>
    
</body>
<script>

    var a = 10;
    var b = a;
    b = 20;
    console.log(a);       // 10
    console.log(b);       // 20


    var obj1 = {name:"admin"};
    var obj2 = obj1;
    obj2.name = "root";
    console.log(obj1);
    console.log(obj2);
</script>
</html>